1. Field of the invention
The present invention relates to a balanced bridge electric gear-shifting mechanism, more particularly, to the balanced bridge electric gear-shifting mechanism, by means of inputting different up and down shifting signals to enact an analog gear-shifting apparatus to generate different voltage potentials, effectively improves the drawbacks of wrong gear shifting induced by a conventional digital gear shifting apparatus by wrongly touching the up and down shifting gear, so as to reduce the gear-shifting duration, enhance the gear-shifting smoothness, and enhance the system reliability and stability.
2. Description of the Prior Arts
In the conventional gear-shifting circuit design for vehicles, two identical circuit apparatuses are used to take advantage of individual input voltage signals to judge if shifting up or down the gear, as a conventional digital gear-shifting system circuit structure 10 illustrated by FIG. 1, while an input end T1 and an input end T2 are connected, its voltage is +5 volts, and at the time of open circuit, its voltage is 0 volt. U is a magnetic hysteresis circuit (such as “Schmitt-Trigger Inverter”), and analog signals will be converted into digital signals via said circuit U in the forms of 0 or 1. At output ends O1 and O2, digital signals are transmitted to the CPU in the system in order to meet the commands requested by the system. When the input ends T1 and T2 are connected, the signals at respectively O1, O2 are 1, otherwise, are 0. CPU is functioning properly while T1 and T2 are individually connected, i.e., T1=5V, T2=0V or vice versa. As the electric gear-shifting system is concerned, while T1 turns on but T2 is open-circuited, it is in up-shifting gear state, on the contrary, it is in downshifting gear state. However, if the driver over-presses the gear-shifting button so as to let T1=T2=5V, and then both of output ends O1 and O2 will transmit 1 to the CPU to result in gear-shifting control failure so as to result in the mal-functioning for the car system.
Besides, in case of digital gear-shifting apparatus for adjusting the up or down shifting gear, while the input signal state is changing, the CPU usually accepts a signal with de-bouncing phenomenon, as suggested in FIG. 2. If the delay time is not ready to be set up, the CPU will receive an up-and-down oscillating digital signal, and the oscillation frequency is subject to change according to the gear-shifting system or circuit specification, as a result the controller must be set up properly for its delay time in order to sample the stable signal after the oscillation. If the delay time is too long, the system will be suffering from its response speed, contrarily, said oscillation signal would be a factor of suffering from the smoothness and gear-shifting timing for vehicles.
As the conventional patents are concerned, for example, in R.O.C. Taiwan utility model patent M285482, “Electric button moving forward gear-switching apparatus on electric vehicle”, said gear-switching apparatus is disposed on the power box on the electric vehicles, and is mixed up with a axis shaft stretching out said power box such that during the vehicles' moving ahead action a button may be used to serve the application of electric operating gear switching. Also, in R.O.C. Taiwan utility patent, M270938, “Moving forward gear switching differential in electric vehicle”, a transmission motor, gearbox, and gear switching control shaft are used to design the gear switching differential, to increase the moving forward speed for electric vehicles. Also, in R.O.C. Taiwan utility patent, M551213, “Gear switching mechanism for electric vehicle”, the designed guiding apparatus in the gear switching mechanism based upon the operating shaft according to the path rotation and vibration, is disclosed to switch and control the forward or reverse rotation of the motor and the speed, and to ensure the reverse gear can be only applied at low-speed driving so as to avoid the high-speed backing risk for children electric vehicles.
In regard to US patents, U.S. Pat. No. 7,228,752, “Structure of a gearbox for all terrain vehicles”, a gear-switching system is disclosed to improve its gearbox structure so as to provide additional torque and power appropriately to improve the engine efficiency. Also, U.S. Pat. No. 7,367,420, “All terrain vehicle having a rider interface for electronic or mechanical shifting”, a gear-switching apparatus for a terrain vehicle is disposed at the left or right ends and said ends are distinguished by their different shapes so as to avoid the wrong press case while the user wears a glove to operate the conventional gear switching button.
Accordingly, as a broad check of domestic or foreign patents, no matter in software design or hardware design, only the improvement of gear switching mechanism and its efficiency is concerned and there lacks a discussion for the interior gear switching circuitry.